Heat storage devices have been known previously and are useful for space heating, particularly where the source of heat is electrical energy. Unfortunately, demand for heat oftentimes occurs at the same time at which other loads are at a maximum, and during times of peak loads, the power companies supplying the electricity will charge a maximum price for their electricity. The heat storing devices allow electricity to be used for generating of heat during off peak hours when the cost of electricity is substantially less than at times of maximum heating load. The heat may be stored for a few hours and then used to heat a room.
One form of heat storing device is disclosed in the Telkes U.S. Pat. No. 2,856,506 which illustrates the possibility of heating blocks of anhydrous sodium sulfate which are used as a heat storage device. Heating occurs with either electrical resistance heaters or with a fuel fired source of heat.
The Jackson U.S. Pat. No. 3,301,251 shows another form of heat storage device with a central opening and metal fins for heating air passing through the opening; the fins being heated by the storage block, and the blocks are heated by a number of resistance heaters laid in grooves between adjacent blocks.
Other forms of heat accumulators and heat storing devices are illustrated in U.S. Pat. Nos. 3,885,126, 3,975,620, and 3,989,927.
Typical heat pump devices are illustrated in U.S. Pat. Nos. 4,012,920 and 4,042,012.